use std::fmt::Write;
use std::path::Path;
use scythe_backend::manifest::{BackendManifest, load_manifest};
use scythe_backend::naming::{
enum_type_name, enum_variant_name, fn_name, row_struct_name, to_pascal_case,
};
use scythe_core::analyzer::{AnalyzedQuery, CompositeInfo, EnumInfo};
use scythe_core::errors::{ErrorCode, ScytheError};
use scythe_core::parser::QueryCommand;
use crate::backend_trait::{CodegenBackend, ResolvedColumn, ResolvedParam};
const DEFAULT_MANIFEST_TOML: &str = include_str!("../../manifests/ruby-pg.toml");
pub struct RubyPgBackend {
manifest: BackendManifest,
}
impl RubyPgBackend {
pub fn new() -> Result<Self, ScytheError> {
let manifest_path = Path::new("backends/ruby-pg/manifest.toml");
let manifest = if manifest_path.exists() {
load_manifest(manifest_path)
.map_err(|e| ScytheError::new(ErrorCode::InternalError, format!("manifest: {e}")))?
} else {
toml::from_str(DEFAULT_MANIFEST_TOML)
.map_err(|e| ScytheError::new(ErrorCode::InternalError, format!("manifest: {e}")))?
};
Ok(Self { manifest })
}
pub fn manifest(&self) -> &BackendManifest {
&self.manifest
}
}
fn ruby_coercion(neutral_type: &str) -> &'static str {
match neutral_type {
"int16" | "int32" | "int64" => ".to_i",
"float32" | "float64" => ".to_f",
"bool" => " == \"t\"",
_ => "",
}
}
impl CodegenBackend for RubyPgBackend {
fn name(&self) -> &str {
"ruby-pg"
}
fn file_header(&self) -> String {
"# frozen_string_literal: true\n\n# Auto-generated by scythe. Do not edit.\n".to_string()
}
fn generate_row_struct(
&self,
query_name: &str,
columns: &[ResolvedColumn],
) -> Result<String, ScytheError> {
let struct_name = row_struct_name(query_name, &self.manifest.naming);
let fields = columns
.iter()
.map(|c| format!(":{}", c.field_name))
.collect::<Vec<_>>()
.join(", ");
let mut out = String::new();
let _ = writeln!(out, "{} = Data.define({})", struct_name, fields);
Ok(out)
}
fn generate_model_struct(
&self,
table_name: &str,
columns: &[ResolvedColumn],
) -> Result<String, ScytheError> {
let name = to_pascal_case(table_name);
self.generate_row_struct(&name, columns)
}
fn generate_query_fn(
&self,
analyzed: &AnalyzedQuery,
struct_name: &str,
columns: &[ResolvedColumn],
params: &[ResolvedParam],
) -> Result<String, ScytheError> {
let func_name = fn_name(&analyzed.name, &self.manifest.naming);
let sql = super::clean_sql(&analyzed.sql);
let mut out = String::new();
let param_list = params
.iter()
.map(|p| p.field_name.clone())
.collect::<Vec<_>>()
.join(", ");
let sep = if param_list.is_empty() { "" } else { ", " };
let _ = writeln!(out, "def self.{}(conn{}{})", func_name, sep, param_list);
let param_array = if params.is_empty() {
"[]".to_string()
} else {
format!(
"[{}]",
params
.iter()
.map(|p| p.field_name.clone())
.collect::<Vec<_>>()
.join(", ")
)
};
match &analyzed.command {
QueryCommand::One => {
let _ = writeln!(
out,
" result = conn.exec_params(\"{}\", {})",
sql, param_array
);
let _ = writeln!(out, " return nil if result.ntuples.zero?");
let _ = writeln!(out, " row = result[0]");
let fields = columns
.iter()
.map(|c| {
let coercion = ruby_coercion(&c.neutral_type);
if c.nullable {
format!(
"{}: row[\"{}\"]&.then {{ |v| v{} }}",
c.field_name, c.name, coercion
)
} else {
format!("{}: row[\"{}\"]{}", c.field_name, c.name, coercion)
}
})
.collect::<Vec<_>>()
.join(", ");
let _ = writeln!(out, " {}.new({})", struct_name, fields);
}
QueryCommand::Many | QueryCommand::Batch => {
let _ = writeln!(
out,
" result = conn.exec_params(\"{}\", {})",
sql, param_array
);
let _ = writeln!(out, " result.map do |row|");
let fields = columns
.iter()
.map(|c| {
let coercion = ruby_coercion(&c.neutral_type);
if c.nullable {
format!(
"{}: row[\"{}\"]&.then {{ |v| v{} }}",
c.field_name, c.name, coercion
)
} else {
format!("{}: row[\"{}\"]{}", c.field_name, c.name, coercion)
}
})
.collect::<Vec<_>>()
.join(", ");
let _ = writeln!(out, " {}.new({})", struct_name, fields);
let _ = writeln!(out, " end");
}
QueryCommand::Exec => {
let _ = writeln!(out, " conn.exec_params(\"{}\", {})", sql, param_array);
let _ = writeln!(out, " nil");
}
QueryCommand::ExecResult | QueryCommand::ExecRows => {
let _ = writeln!(
out,
" result = conn.exec_params(\"{}\", {})",
sql, param_array
);
let _ = writeln!(out, " result.cmd_tuples.to_i");
}
}
let _ = write!(out, "end");
Ok(out)
}
fn generate_enum_def(&self, enum_info: &EnumInfo) -> Result<String, ScytheError> {
let type_name = enum_type_name(&enum_info.sql_name, &self.manifest.naming);
let mut out = String::new();
let _ = writeln!(out, "module {}", type_name);
for value in &enum_info.values {
let variant = enum_variant_name(value, &self.manifest.naming);
let _ = writeln!(out, " {} = \"{}\"", variant, value);
}
let all_values = enum_info
.values
.iter()
.map(|v| enum_variant_name(v, &self.manifest.naming))
.collect::<Vec<_>>()
.join(", ");
let _ = writeln!(out, " ALL = [{}].freeze", all_values);
let _ = write!(out, "end");
Ok(out)
}
fn generate_composite_def(&self, composite: &CompositeInfo) -> Result<String, ScytheError> {
let name = to_pascal_case(&composite.sql_name);
let mut out = String::new();
if composite.fields.is_empty() {
let _ = writeln!(out, "{} = Data.define()", name);
} else {
let fields = composite
.fields
.iter()
.map(|f| format!(":{}", f.name))
.collect::<Vec<_>>()
.join(", ");
let _ = writeln!(out, "{} = Data.define({})", name, fields);
}
Ok(out)
}
}